Nostalgia & History > Wheel gauge

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Date: 05/06/04 11:59
Re: A day in the life of a pool freight engineer...Part 1
Author: Steamjocky
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WichitaJct Wrote:
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> steamjockey said: calibrating the speedo (I carry
> a wheel gauge with me) and footage counter,
>
> could you explain this ? Thanks



This picture illustrates a gauge similar to what Steamjocky refers to in his explanation. My Road Foreman gave it to me many years ago. Amtrak's Genesis series engines are very easy to calibrate through the IFD screen and I would check the wheel diameter and reset the speedometer if necessary every trip unless we were really pressed for time on a crew change because of a late train. The only down side (the GE design engineers must have really had to work hard to come up with this!) is that the change made on the screen doesn't take effect until one reboots the computer which kills the HEP to the train for a short time until it can be restarted. A few years ago I had to stop calibrating the speedometers because some dimwitted individual decided that doing so was tampering with a safety device, a FRA no-no. I guess they would rather have erroneous speedometers in service so that when they are gunning you to the tenth or hundredth of a MPH they have a better chance of finding you in error and writing you up for an investigation.

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Just looks like what it is, a wheel gauge. You can measure the tread, width, etc. I didn't notice if this had a flange gauge to see if you can "shave" with them, an FRA violation.

The distance to the witness groove is to get the exact dia. at that moment. This is used to check the speedo and make sure everything is correct. All wheels have a groove on an engine. Its also used to see how much wear the wheel has left.

Nudge

My gauge is a little different that Jim's but it's basically the same. I'd try to scan mine but it's so old I don't think you could read the numbers on it. Mine is made of black plastic. Is yours plastic Jim, or is it metal?

steamjocky

Steamjocky Wrote:
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> Is yours
> plastic Jim, or is it metal?
>
> steamjocky
>


It's metal (aluminum).

You know after 5,373 downloads over the 6 years I spent upstairs....you can get where you can almost look at the wheel and tell the size.....now that is bad...huh....:o)

Jim,
My guage is a Stanley 3' tape measure. I keep track of the wheel diameters on our fleet on locomotives and often check UP power I'm on except for AC units for the same reason you don't. I have found a fair number of the UP locomotives I've been on have the wrong wheel diameter because whoever measured it did not realize that they were measuring wheels with a 38" witness groove. Two of the best tools a hogger can have - a tape measure and a stop watch!

Roustabout out


Jim700 Wrote:
>
> This picture illustrates a gauge similar to what
> Steamjocky refers to in his explanation. My Road
> Foreman gave it to me many years ago. ....
> ...A few years ago I had to stop
> calibrating the speedometers because some
> dimwitted individual decided that doing so was
> tampering with a safety device, a FRA no-no. I
> guess they would rather have erroneous
> speedometers in service so that when they are
> gunning you to the tenth or hundredth of a MPH
> they have a better chance of finding you in error
> and writing you up for an investigation.

Nice thing now up the Valley is the 1/4 mile markers again.....quick check on a mile without going the mile...

I'm trying to figure out what is meant by a 'witness groove'. Is this a groove cut into the wheel that encircles the wheel like a ring? Sort of like the tread on a tire?

Sorry to be so inartful regarding the question, but it has been some time since I ran a gauge lab at Texas Instruments and the correct terms have been forgotten.

john1082 Wrote:
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> I'm trying to figure out what is meant by a
> 'witness groove'. Is this a groove cut into the
> wheel that encircles the wheel like a ring? Sort
> of like the tread on a tire?

Yes, John, it is. It's on the outer face of the wheel. The short end of the gauge is laid across the wheel tread area with the long end of the gauge against the outward face of the wheel and pointing toward the axle center. At some point on the measuring scale one of the marks will be directly over or nearest to the center of the witness grove.